In researching the forces that act on flying birds, scientists studied the motion of cockatiels' bodies as they fly in horizontal flight. As the birds beat their wings, their bodies move up and down. (Figure 1) shows the vertical acceleration of a cockatiel's body during one wing beat, consisting of an upstroke followed by a downstroke. If the bird's mass is 97 g
, what is the maximum net vertical force exerted on the bird?